Pye P45. That capacitor? - UK Vintage Radio Repair and Restoration Discussion Forum

Dick Glennon · 13th Nov 2017, 11:25 pm

Hello again, Could someone please verify that capacitor in a Pye P45 please.

Thanks, Dick.

Boater Sam · 14th Nov 2017, 11:12 am

On Trader sheet 1085, C43 and C44 are marked as audio coupling. C46 also needs to be above suspicion.
I can see your confusion, the switching makes it less obvious.
The Pye manufacturers sheet is very difficult to follow, there may be discrepancies between the 2 sheets on component values for capacitors.
As there is no preamp audio stage, there is not the normal arrangement of a capacitor from the preamp anode to the output grid 1 via the volume control, the detector diode feeds the output directly.

paulsherwin · 14th Nov 2017, 11:15 am

As Sam says, there is no classic 'that capacitor' in a short superhet design like the P45.

ms660 · 14th Nov 2017, 11:15 am

Which capacitor...

If you mean the g1 coupling capacitor for the audio output valve then technically there's two of them (Trader sheet) C25 and C30, C25 is only in circuit when certain settings of the tone control are selected.

For an audio output valve damaging capacitor check out C28.

Lawrence.

G8HQP Dave · 14th Nov 2017, 12:00 pm

P45 does not have 'that capacitor', as there is no previous stage anode.

Boater Sam · 14th Nov 2017, 12:44 pm

Corrections Dick, sorry I was looking at the gram version, C25, C28 & C30 need to be leak free, but as long as C28 is good, there should be no problems.

13th Nov 2017, 11:25 pm	#1
Dick Glennon Hexode Join Date: Oct 2006 Location: Edenderry, Republic of Ireland. Posts: 428	Pye P45. That capacitor? Hello again, Could someone please verify that capacitor in a Pye P45 please. Thanks, Dick.

14th Nov 2017, 11:12 am	#2
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Pye P45. That capacitor? On Trader sheet 1085, C43 and C44 are marked as audio coupling. C46 also needs to be above suspicion. I can see your confusion, the switching makes it less obvious. The Pye manufacturers sheet is very difficult to follow, there may be discrepancies between the 2 sheets on component values for capacitors. As there is no preamp audio stage, there is not the normal arrangement of a capacitor from the preamp anode to the output grid 1 via the volume control, the detector diode feeds the output directly.

14th Nov 2017, 11:15 am	#3
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Pye P45. That capacitor? As Sam says, there is no classic 'that capacitor' in a short superhet design like the P45.

14th Nov 2017, 11:15 am	#4
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Pye P45. That capacitor? Which capacitor... If you mean the g1 coupling capacitor for the audio output valve then technically there's two of them (Trader sheet) C25 and C30, C25 is only in circuit when certain settings of the tone control are selected. For an audio output valve damaging capacitor check out C28. Lawrence.

14th Nov 2017, 12:00 pm	#5
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: Pye P45. That capacitor? P45 does not have 'that capacitor', as there is no previous stage anode.

14th Nov 2017, 12:44 pm	#6
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Pye P45. That capacitor? Corrections Dick, sorry I was looking at the gram version, C25, C28 & C30 need to be leak free, but as long as C28 is good, there should be no problems.